Sounds like the first episode of Smallville.
There have been multiple sonic booms and explosions, one at 8:30 AM also. Meteorologist attributing to debris from Comet Thatcher and the Lyrid Meteor Shower.
More could be coming, apparently.
http://www.sacbee.com/2012/04/22/4433508/explosions-in-the-sierra-today.html
It does sound like Smallville, doesn’t it?